The present invention is directed generally to the manufacture of pre-hung doors, and more particularly to an automated system capable of selecting a door from one of a number of loading stations for pickup and transport to a work station.
In the construction industry it has long been found expedient to order, and have on hand at the construction site, pre-prepared or pre-hung doors of various sizes and handedness (i.e., the sides of a door at which hinge and door locks are installed). A builder may require several sizes and types of doors for a particular house or building being constructed. For example, some doors may need to be pre-prepared only to have the necessary lock and/or latch hole drilling on door edge, and hinge routing at the other, so that they open away to the right. Other doores may be needed to open away to the left. Thus, door locks, latches, and hinges for the former need to be installed on edges opposite to those for the latter. (Installation may either be at the construction site or by the manufacturer.)
The manufacture of doors, including pre-prepared and pre-hung doors, can be labor intensive. Thus, to reduce costs, the door manufacturing industry has resorted to automation wherever possible in order to reduce many of the labor-intensive aspects of door manufacture, providing automated workstations at which the various door preparation activities can take place. An example of such automated door preparation systems can be found in U.S. Pat. No. 4,254,895.
Today, however, door manufacture still has costly, labor-intensive aspects. Transporting doors to the workstation is one example. Although conveyors can be used to transport a door to the workstation, someone must still make door selection (size, style, hinged side, etc.) to place it on the conveyor for transport to the workstation. An order for doors may include 20 doors of one size, 20 more doors of the same size but with a different handedness (i.e., the edge on which the hinges and locks are to be placed), and 20 more doors of a different size. Someone must make the selection, place them on the conveyor belt (or other transport means) for transport to the workstation, and then off-load the doors from the conveyor belt to the workstation for preparing the doors.
Accordingly, there is needed in the door manufacturing industry apparatus that can conveniently and quickly transport different sizes of doors to a workstation without too much manual intervention.